Fig. 4: XPS and In-situ measurements.

XPS spectra for a Ti 2p of MCOF-Ti₆Cu₃, Ti₆ and b Cu 2p of MCOF-Ti₆Cu₃, Cu₃. In-situ XPS spectra of c Ti 2p and d Cu 2p for the simulated solar-driven CO₂ reduction process over MCOF-Ti₆Cu_3. e In-situ DRIFTS spectra for the simulated solar-driven CO₂ reduction process over MCOF-Ti₆Cu₃.